In a conventional sample analyzing method, a reaction liquid is prepared by reacting a sample with a reagent, and then the reaction liquid is subjected to optical analyzation. To analyze a sample by this method, use may be made of an analytical tool for providing a reaction field. Such an analytical tool may be set into an analyzer configured to analyze the reaction liquid. When a small amount of sample is to be analyzed, a microdevice, formed with minute flow paths, is used as an analytical tool.
Referring now to FIG. 7, the conventional microdevice 9 includes a plurality of radially arranged flow paths 90 for moving a sample by capillarity (see Patent Document 1, for example). In the microdevice 9, a branch flow path 91 branches off from an intermediate portion of each flow path 90, and the end (downstream end in the sample flow direction) of each flow path 90 is connected to an annular common path 92. The branch flow paths 91 are configured to communicate with the outside. When communication is provided between the inside and the outside of the branch flow paths 91, the sample will flow into the branch flow paths 91, as shown in FIG. 8A. In each of the flow paths 90, the sample moves to the portion (branch portion) before a reaction portion 93 (provided with a reagent portion). The common path 92 is also arranged to communicate with the outside. Thus, in discharging gas from the common path, the sample is collectively introduced into the reaction portions 93 of the flow paths 90, as shown in FIG. 8B, and reacts with the reagent in the reagent portions 93.
However, the flow paths 90 of the microdevice 9 may have variations in e.g. volume (cross sectional area) due to an error in the manufacturing process, whereby the sample may flow at different speeds in the flow paths 90. If the sample moves at a higher speed through a certain flow path, thereby reaching the common path 92 earlier, only the particular portion of the sample may fill the path 92. In such a case, the capillary force becomes weaker in the other flow paths having lower sample moving speeds. In these flow paths, the movement of the sample may stop before a sufficient amount of sample has been supplied to the reaction portion 93, or the speed of the sample flowing into the reaction portion 93 may be considerably reduced. In these cases, the measurement accuracy for the slow-sample flow paths may deteriorate. In particular, the flow paths 90 of the microdevice 9 are very small. Consequently, the size variation due to the manufacturing error can significantly affect the speed of sample movement, thereby making the above problem more serious.
Patent Document 1: JP-A-2004-117178